JP3507459B2 - Illumination apparatus, exposure apparatus, and device manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device, an exposure device and a device manufacturing method, and more particularly to semiconductor devices such as LSIs, image pickup devices such as CCDs, display devices such as liquid crystal panels and detection devices such as magnetic heads. The present invention relates to an illuminator, an exposure apparatus, and a device manufacturing method for appropriately illuminating a device pattern on a reticle surface when manufacturing various devices.

[0002]

2. Description of the Related Art Recent progress in fine processing technology is remarkable, and the resolution required for lithography is 0.3 μm or 0.2.
A very small size of 5 μm is required.

Therefore, the present applicant has filed Japanese Patent Application Laid-Open No. 5-283331.
In Japanese Patent Laid-Open No. 7-74, there is proposed an illuminating device capable of improving the resolution of a projection exposure apparatus for lithography.

FIG. 4 shows an illumination device (projection exposure device) disclosed in Japanese Patent Laid-Open No. 5-283317.

In FIG. 4, reference numeral 1 denotes a high-intensity ultra-high pressure mercury lamp that emits ultraviolet rays or far ultraviolet rays, and is a light emitting portion 1 a of the mercury lamp 1.
Is near the first focus of the elliptical mirror-2. The light emitted from the mercury lamp 1 is reflected and condensed by the elliptical mirror-2, reflected by the cold mirror-3, and then the image of the light emitting portion 1a (light emitting portion) near the second focus 4 of the elliptical mirror-2. Image) 1b is formed. Cold Mira-3 is formed by forming a multilayer film that transmits infrared light and reflects ultraviolet light on a glass substrate.

Reference numeral 101 denotes an image forming system composed of lens systems 5 and 9, and a light emitting portion image 1 formed near the second focal point 4.
b is a light incident surface 10a of the optical integrator 10.
The image is formed above. The lens system 9 is a zoom lens and is configured to change the magnification of the image forming system 101. Reference numeral 7 denotes a holding member for the optical element, which is configured so that a plurality of optical elements such as a conical prism and a polygonal pyramid prism can be switched and arranged in the optical path. Lens system 5
Makes the position of the opening of the elliptical mirror-2 and the position of the holding member 7 in an optically substantially conjugate positional relationship.

The optical integrator 10 is a multi-beam forming member that forms a large number of light beams, and is formed by arranging a large number of minute lenses two-dimensionally along a plane orthogonal to the optical axis. The secondary light source 10c is formed near the surface 10b. Reference numeral 11 denotes a diaphragm member having a plurality of aperture members having different shapes and sizes, and the diaphragm member 11 has a mechanism capable of switching the aperture members to be inserted into the optical path.

Reference numeral 14a denotes a lens system, and the lens system 14a
Collects the light beam from the light exit surface 10b of the optical integrator 10. The condenser lens system 14 including the lens system 14a and the collimator lens 14b is a light flux from the light exit surface 10b via the diaphragm member 11 and the mirror 13, and is an illuminated surface placed on the reticle stage 16. A certain reticle 15 is illuminated with a caller.

A projection optical system 17 includes a reticle 15
The pattern depicted in FIG. 3 is reduced and projected onto the photosensitive surface of the wafer 18 placed on the wafer chuck 19. 20 is
The wafer chuck 19 is mounted on the wafer chuck 19. The secondary light source 10c near the light exit surface 10b of the optical integrator 10 forms an image near the pupil 17a of the projection optical system 17 by the condenser lens system 14.

The illuminating device of FIG. 4 rotates the holding member 7 of the optical element according to the directionality of the fine pattern drawn on the reticle 15 and the resolution line width, etc. by changing the magnification of the imaging system 101 as required is inserted a desired optical element in the optical path, FIG. 5 (a), the
As shown in (B) and (C), the light intensity distribution on the light incident surface 10a of the optical integrator 10 is changed to 2
The light intensity distribution (illumination method) of the secondary light source is changed. Figure 5
The shaded area in the middle is a region where the light intensity is high.

[0011]

In the above illumination device, the shape and size of the aperture of the diaphragm member 11 is changed, the optical element held by the holding member 7 is switched, and the imaging system 1 is used.
If the imaging magnification of 01 is changed , non-negligible illuminance unevenness occurs on the reticle 15 surface or the wafer 18 surface.
There is a case . It is an object of the present invention to provide an illumination device, an exposure device, and a device manufacturing method capable of reducing this type of uneven illuminance .

[0012]

In order to achieve the above object, an illumination device of the present invention forms an elliptical mirror that forms a light source image by using a light beam from a light source, and forms a multi-light beam by using incident light. An optical integrator and an imaging optical system that re-images the light source image on an incident surface of the optical integrator or in the vicinity thereof, and in an illumination device that illuminates a surface to be illuminated with the multi-beam, the imaging optical system
Is in order from the light source side along the optical axis of the imaging optical system,
A first lens system having a front focus position at or near the position where the light source image is formed, a first transparent wedge, and a second transparent wedge having a wedge angle substantially equal to that of the first transparent wedge. first light deflecting member comprises a second lens system for the entrance surface or its vicinity of the optical integrator and the first light deflection member or near the front focal position and back focal position, the first light deflection member Near
In order to convert the light flux from the light source into a ring-shaped light flux,
A cone for illuminating the optical integrator
Second light deflecting member with a circular deflection surface can be inserted into and removed from the optical path
Provided, wherein the first transparent wedge and the second transparent wedge can rotate individually about said optical axis, said first transparent wedge and the second transparent wedge By rotating, the incident position of the light beam from the light source on the optical integrator is changed.

Further , another lighting device of the present invention is a light source.
Incident from an elliptical mirror that forms a light source image using these light fluxes
Optical integrator that uses light to form multiple beams
And the light source image of the optical integrator
Imaging optics that re-images on or near the plane of incidence
In the lighting device that illuminates the surface to be illuminated with the multiple luminous flux.
The imaging optical system is arranged along the optical axis of the imaging optical system.
If the position where the light source image is formed in order from the light source side
The first lens system having the front focus position in the vicinity of the first lens system
Substantially transparent wedge and the first transparent wedge and substantially wedge
A first light deflecting member having second transparent wedges with equal angles;
The first light deflecting member or the vicinity thereof is set as the front focus position, and
The input surface of the optical integrator or its vicinity.
It has a second lens system at the rear focal position,
In the vicinity of the first light deflecting member, the light flux from the light source is
Optical integrator
Second light deflector having a conical deflection surface for illuminating
The material is removably installed in the optical path, and the first transparent
The rust and the second transparent wedge are centered on the optical axis
And individually rotatable, the front and the first transparent wedge
The rotation of the second transparent wedge causes the light source to
Incident of light flux from the optical integrator to the optical integrator
Characterized by changing the position .

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

Further, the exposure apparatus of the present invention is characterized in that the mask is illuminated by any one of the above-mentioned illumination apparatuses and the pattern of the illuminated mask is projected on the wafer by the projection optical system.

The device manufacturing method of the present invention is characterized by including the steps of exposing a wafer with a device pattern by the above-described exposure apparatus and developing the exposed wafer.

[0023]

[0024]

[0025]

[0026]

1 is a diagram showing a first embodiment of the present invention.

In FIG. 1, reference numeral 1 is a high-intensity ultra-high pressure mercury lamp that emits ultraviolet rays and far ultraviolet rays, and is a light emitting portion 1 a of the mercury lamp 1.
Is near the first focus of the elliptical mirror-2. The light emitted from the mercury lamp 1 is reflected and condensed by the elliptical mirror-2, reflected by the cold mirror-3, and then the image of the light emitting portion 1a (light emitting portion) near the second focus 4 of the elliptical mirror-2. Image) 1b is formed. Cold Mira-3 is formed by forming a multilayer film that transmits infrared light and reflects ultraviolet light on a glass substrate. Mercury lamp 1
Can be moved in the optical axis direction, and for example, the position in the optical axis direction can be adjusted so that the amount of light flux incident on the light incident surface 10a of the optical integrator 10 is maximized.

Reference numeral 101 denotes an optical system such as an image forming system composed of lens systems 5 and 9, and a light emitting portion image 1b formed in the vicinity of the second focal point 4 on the light incident surface 10a of the optical integrator 10. Or it is re-imaging in the vicinity. The front focus position of the lens system 5 substantially coincides with the position of the light emitting unit image 1b formed near the second focus 4. The lens system 9 (irradiation optical system) is a zoom lens and is configured to change the magnification of the image forming system 101. Reference numeral 7 denotes a holding member for the optical element, which is configured so that a plurality of optical elements (second light deflecting members) such as a conical prism and a polygonal pyramid prism can be switched and arranged in the optical path. Lens system 5
The (light receiving optical system) makes the position of the opening of the elliptical mirror-2 and the position of the holding member 7 in an optically substantially conjugate positional relationship. FIG. 2 shows a holding member 7 and a plurality of optical elements 6 held by the holding member 7.
a to 6f, the holding member 7 is a turret plate that rotates around a rotation axis passing through the center by a motor (not shown), the optical element 6a is a conical prism, and the optical element 6b is an apex angle more than the optical element 6a. Is a small conical prism, the optical element 6c is a quadrangular pyramid prism, the optical element 6d is a quadrangular pyramid prism having a larger apex angle than the optical element 6c, the optical element 6e is an eight-sided pyramid prism, and the optical element 6f is a plane parallel plate (this portion is transparent). It may be the opening of).

The optical integrator 10 is a multi-beam forming member that forms a large number of light beams, and is formed by arranging a large number of minute lenses two-dimensionally along a plane orthogonal to the optical axis. The secondary light source 10c is formed near the surface 10b. The light incident surface of the optical integrator 10 is at the focal point on the rear side of the lens system 9. Reference numeral 11 denotes a diaphragm member having a plurality of aperture members having different shapes and sizes, and the diaphragm member 11 has a mechanism capable of switching the aperture members to be inserted into the optical path. The opening shapes of the plurality of opening members correspond to the optical elements 6a to 6f and are ring-shaped, 4
Includes one hole, eight holes, and one hole.

Reference numeral 14a denotes a lens system, and the lens system 14a
Collects the light beam from the light exit surface 10b of the optical integrator 10. The condenser lens system 14 including the lens system 14a and the collimator lens 14b is a light flux from the light exit surface 10b via the diaphragm member 11 and the mirror 13, and is an illuminated surface placed on the reticle stage 16. A certain reticle 15 is illuminated with a caller.

A projection optical system 17 includes a reticle 15
The pattern depicted in FIG. 3 is reduced and projected onto the photosensitive surface of the wafer 18 placed on the wafer chuck 19. 20 is
It is an XY stage, and the wafer chuck 19 is placed on it. The secondary light source 10c near the light exit surface 10b of the optical integrator 10 forms an image near the pupil 17a of the projection optical system 17 by the condenser lens 14.

The illumination device of FIG. 1 is depicted on a reticle 15.
Depending on the directionality of the fine pattern and the resolution line width, etc.
The element holding member 7 is rotated to rotate the plurality of optical elements 6a to 6f.
Insert the desired optical element in the optical path into the optical path and
Depending on the magnification of the imaging system 101,5
As shown in (A), (B), and (C),
The light intensity distribution on the light incident surface 10a of the integrator 10 is changed.
Furthermore, the light intensity distribution (illumination method) of the secondary light source is changed.
It Figure5The shaded area is a region where the light intensity is high.

A feature of the illuminating device shown in FIG. 1 is that an optical axis adjusting device 21 (first light deflecting member) is provided near the optical element holding member 7. The optical axis adjusting device 21 includes two wedge glasses 21a and 21b having substantially the same wedge angles, and the two wedge glasses 21a and 21b are both on the first surface and the optical axis which are perpendicular to the optical axis. And a second surface inclined with respect to the second surface. The wedge angle refers to the angle formed by the first surface and the second surface. The optical axis adjusting device 21 individually rotates each of the wedge glasses 21a and 21b by using a driving device (not shown) with the optical axis as a rotation axis, and adjusts a rotation angle around each optical axis. By this adjustment, the entire light flux passing through the optical axis adjusting device 21 can be deflected in a desired direction by an angle, the incident position of the entire light flux on the light incident surface 10a of the optical integrator 10 is changed, and the light incident surface 10a is changed. The entire light intensity distribution of can be moved.

In the illumination device of FIG. 1, when the position of the entire light flux (entire light intensity distribution) incident on the optical integrator 10 is changed, the reticle 15 which is the irradiated surface is changed.
The illuminance distribution on the wafer 18 changes. In the present embodiment, this is utilized to minimize the uneven illuminance on the wafer 18.
So that adjusting wedge glass 21a, the rotation angle of 21b as that.

FIG. 3 is an explanatory view showing the function of the optical axis adjusting device 21. FIG. 3A is a diagram showing a case where the plane parallel plate 6f is inserted in the optical path and the two wedge glasses 21a and 21b are set at positions where the wedge angles are offset from each other.
FIG. 3B shows a wedge glass 21b from the state of FIG. 3A.
It is a figure which shows the case where is rotated by a certain angle. Figure 3
The drawings on the right side of (A) and (B) schematically show the light intensity at the light incident surface 10a of the optical integrator 10. From this drawing, the wedge glasses 21a and 21b are respectively set at appropriate angles. The optical integrator 1 is rotated by deflecting the entire light beam by a certain angle in a desired direction.
The light intensity distribution on the light incident surface 10a of 0 is set to the optical axis (center)
It turns out that can be eccentric to. This is because when the incident angle of the entire light flux entering the lens system 9 is changed, the light incident surface 1 of the optical integrator 10 for the entire light flux is changed.
This is because the position of incidence on 0a changes.

Hereinafter, the illuminance using the optical axis adjusting device 21
An example of these adjustment procedures will be shown. 1. Determine the lighting method. 2. Change the optical system so that it is optimal for the determined lighting method. Selection of optical elements (6a-6f). Setting of magnification of the image forming system 101 (determination of zoom position of the lens system 9). Aperture 11
(Selection of opening shape and size). Change the position of the mercury lamp 1 in the optical axis direction. etc 3. Remove the reticle 15 from the stage 16 and move the XY stage.
An illuminance unevenness measuring device (not shown) on the screen 20 measures the illuminance distribution on the image plane of the projection optical system 17. 4. From the measured illuminance distribution, the rotation angles of the wedge glasses 21a and 21b that minimize the illuminance unevenness are calculated, and the wedge glasses 21a and 21b are rotated to designated positions by a driving device (not shown).

The above measurement may be performed on the object surface where the pattern surface of the reticle 15 is located.

In the above adjustment procedure, the illuminance distribution is measured every time the lighting method is switched, and the rotation angles of the wedge glasses 21a and 21b are calculated from the measurement results.
The rotation angles of a and 21b may be obtained and stored in a memory, and the wedge glasses 21a and 21b may be automatically rotated by a predetermined angle when switching the illumination method.

Wedge glass 21 is used for each lighting method.
Instead of having the designated rotation angles of a and 21b, in all the illumination methods to be used, the rotation angle at which the illuminance unevenness becomes better on average is obtained, and the wedge glass 21a and 21b may be fixed to that angle.

In the present embodiment, the optical axis adjusting device 21 is composed of two wedge glasses having the same angle.
It may be composed of three or more wedge glasses. In this case, the wedge angle of the wedge glass having the largest wedge angle needs to be equal to or less than the sum of the wedge angles of the other two or more wedge glasses.

In this embodiment, the optical axis adjusting device 21 is arranged closer to the light source side than the optical elements 6a to 6f, but the optical axis adjusting device 21 is arranged closer to the optical integrator 10 side than the optical elements 6a to 6f. May be. The point is that the optical integrator 10 may be arranged at a position where the incident position can be changed without significantly changing the incident angle to the light incident surface 10a of the optical integrator 10.

In each of the above embodiments, when the illumination method is changed, the wedge glass is used to adjust the illuminance unevenness on the surface to be illuminated to the minimum. However, this is not necessarily the case, and, for example, changes over time in the optical system ( Lens and mirror
(Characteristic change of lighting and change of luminance distribution of arc of lamp)
Therefore, when the illuminance unevenness occurs, it may be automatically adjusted .

In each of the above embodiments, the optical elements 6a to 6f are used.
However, the number is not limited to this. The present invention can be applied even when there is no optical element.

Next, an embodiment of a device manufacturing method using the projection exposure apparatus of FIGS. 1 to 3 will be described.

FIG. 6 shows a manufacturing flow of devices (semiconductor chips such as IC and LSI, magnetic heads, liquid crystal panels and CCDs). In step 1 (circuit design), a semiconductor device circuit is designed. In step 2 (mask production), a mask (reticle 15) on which the designed circuit pattern is formed
To produce. On the other hand, in step 3 (wafer manufacturing), a wafer (wafer-18) is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by the lithography technique using the mask and the wafer prepared above. The next step 5 (assembly) is called the post process,
This is a step of forming a chip using the wafer prepared in step 4, and includes an assembly step (dicing, bonding), a packaging step (chip encapsulation) and the like. In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and a durability test. Through these steps, the semiconductor device is completed and shipped (step 7). FIG. 8 shows a detailed flow of the wafer process. In step 11 (oxidation), the surface of the wafer (wafer-18) is oxidized. In step 12 (CVD), an insulating film is formed on the surface of the wafer. In step 13 (electrode formation), the wafer
An electrode is formed on the top by vapor deposition. In step 14 (ion implantation), ions are implanted in the wafer. In step 15 (resist processing), a resist (photosensitive material) is applied to the wafer. In step 16 (exposure), the projection exposure apparatus exposes the wafer with an image of the circuit pattern of the mask (reticle 15). In step 17 (development), the exposed wafer is developed. In step 18 (etching), parts other than the developed resist are scraped off. In step 19 (resist stripping), the resist that is no longer needed after etching is removed. By repeating these steps, a circuit pattern is formed on the wafer.

By using the manufacturing method of this embodiment, it becomes possible to manufacture a highly integrated device which has been difficult in the past.

[0047]

When the present invention is applied to the projection projection exposure apparatus for manufacturing semiconductor devices, the electronic circuit pattern on the reticle surface can be projected onto the wafer surface with high accuracy.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a lighting device of the present invention.

FIG. 2 is a diagram showing an example of an optical element of the lighting device of FIG.

FIG. 3 is an explanatory view of the optical axis adjusting device of FIG.

FIG. 4 is a diagram showing a conventional lighting device.

5 is an explanatory diagram showing how to switch an illumination method in the illumination device of FIG. 4. FIG.

FIG. 6 is a diagram showing a flow of a device manufacturing method.

FIG. 7 is a diagram showing the wafer process of FIG. 6;

[Explanation of symbols]

1 Mercury lamp 2 Elliptical mirror 3 Cold Mira 5, 9 lens system 6a to 6f optical element 7 Optical element holding member (turret plate) 10 Optical integrator 11 Aperture member 15 reticle 17 Projection lens 18 wafers 21a, 21b Wedge glass 22 Parallel plane plate 23a-23f wedge glass

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI G03F 7/20 521 H01L 21/30 515D G02B 7/18 A (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/027

Claims (4)

(57) [Claims] 1. A light source image is formed using a light flux from a light source.
Ellipsoidal mirror and an optical
Optical integrator and the light source image
Image again at or near the entrance surface of the cal integrator
And an imaging optical system for
In the illuminating device for illuminating, the imaging optical system is configured such that the light is emitted along an optical axis of the imaging optical system.
From the source side, the position where the light source image is formed or
Lens system with the front focus position near the lens, the first transparent
The wedge angle is substantially equal to that of the wedge and the first transparent wedge.
A first light deflecting member having a new transparent wedge, the first
The optical deflection member or the vicinity thereof is set as the front focus position, and
Behind the incident surface of the optical integrator or its vicinity
A second lens system at a focal position is provided, and the light flux from the light source is divided into a plurality of light fluxes in the vicinity of the first light deflection member, and the plurality of light fluxes are deflected in mutually different directions. Thus, a second light deflecting member that allows the plurality of light beams to enter different positions of the optical integrator is detachably provided in the optical path, and the first transparent wedge and the second transparent wedge are
Individually rotatable about the optical axis, the first transparent wedge and the second transparent wedge rotate.
Turning the optical beam from the light source
A lighting device characterized by changing the incident position on the cal integrator . 2. A light source image is formed using a light flux from a light source.
Ellipsoidal mirror and an optical
Optical integrator and the light source image
Image again at or near the entrance surface of the cal integrator
And an imaging optical system for
In the illuminating device for illuminating, the imaging optical system is configured such that the light is emitted along an optical axis of the imaging optical system.
From the source side, the position where the light source image is formed or
Lens system with the front focus position near the lens, the first transparent
The wedge angle is substantially equal to that of the wedge and the first transparent wedge.
A first light deflecting member having a new transparent wedge, the first
The optical deflection member or the vicinity thereof is set as the front focus position, and
Behind the incident surface of the optical integrator or its vicinity
A second lens system at a focal position is provided, and a conical deflection for converting the light beam from the light source into a ring-shaped light beam and irradiating the optical integrator in the vicinity of the first light deflection member. A second light-deflecting member having a surface is detachably provided in the optical path, and the first transparent wedge and the second transparent wedge are separated from each other.
Individually rotatable about the optical axis, the first transparent wedge and the second transparent wedge rotate.
Turning the optical beam from the light source
A lighting device characterized by changing the incident position on the cal integrator . 3. An exposure apparatus, wherein a mask is illuminated by the illumination device according to claim 1 or 2 , and the pattern of the illuminated mask is projected onto a wafer by a projection optical system. 4. A device manufacturing method comprising: exposing a wafer with a device pattern by the exposure apparatus according to claim 3; and developing the exposed wafer.